datastructures aptitude-part1

[abeetha.m]

1. [/i]What is data structure?[/i]


A
data structure is a way of organizing data that considers not only the items
stored, but also their relationship to each other. Advance knowledge about the
relationship between data items allows designing of efficient algorithms for
the manipulation of data.





2. [/i]List out the areas in which data structures
are applied extensively? [/i]


Ø
Compiler Design,


Ø
Operating System,


Ø
Database Management System,


Ø
Statistical analysis package,


Ø
Numerical Analysis,


Ø
Graphics,


Ø
Artificial Intelligence,


Ø
Simulation





3. [/i]What are the major data structures used in
the following areas : RDBMS, Network data model & Hierarchical data model.[/i]


Ø
RDBMS
– Array (i.e. Array of structures)


Ø
Network data model – Graph


Ø
Hierarchical data model – Trees





4. [/i]If you are using C language to implement the
heterogeneous linked list, what pointer type will you use?[/i]


The heterogeneous linked
list contains different data types in its nodes and we need a link, pointer to
connect them. It is not possible to use ordinary pointers for this. So we go
for void pointer. Void pointer is capable of storing pointer to any type as it
is a generic pointer type.





5. [/i]Minimum number of queues needed to implement
the priority queue?[/i]


Two.
One queue is used for actual storing of data and another for storing
priorities.





6. [/i]What is the data structures used to perform
recursion?[/i]


Stack.
Because of its LIFO (Last In First Out) property it remembers its ‘caller’ so
knows whom to return when the function has to return. Recursion makes use of
system stack for storing the return addresses of the function calls.


Every
recursive function has its equivalent iterative (non-recursive) function.[/i]
Even when such equivalent iterative procedures are written, explicit stack is
to be used.





7. [/i]What are the notations used in Evaluation of
Arithmetic Expressions using prefix and postfix forms?[/i]


Polish and Reverse Polish notations.





8. [/i]Convert the expression ((A + B) * C – (D – E) ^ (F + G)) to equivalent Prefix
and Postfix notations.[/i]


Prefix Notation:


^ - * +ABC - DE + FG


Postfix
Notation:


AB + C * DE - - FG + ^




9. [/i]Sorting is not possible by using which of
the following methods?[/i]


(a)
Insertion [/i]


(b)
Selection [/i]


(c)
Exchange [/i]


(d)
Deletion[/i]





(d) Deletion.


Using
insertion we can perform insertion sort, using selection we can perform
selection sort, using exchange we can perform the bubble sort (and other
similar sorting methods). But no sorting method can be done just using
deletion.





10. [/i][img]file:///C:%5CDOCUME%7E1%5CADMINI%7E1%5CLOCALS%7E1%5CTemp%5Cmsohtml1%5C03%5Cclip_image001.gif[/img]A
binary tree with 20 nodes has
null branches?[/i]


21


Let us take a tree with 5 nodes
(n=5)

	[img]file:///C:%5CDOCUME%7E1%5CADMINI%7E1%5CLOCALS%7E1%5CTemp%5Cmsohtml1%5C03%5Cclip_image002.gif[/img]

It will have
only 6 (ie,5+1) null branches. In general,


A
binary tree with n[/b] nodes has exactly
n+1[/b] null nodes. [/i]